1. Technical Field
The present design pertains to a structural modification to handcuffs, especially, a handcuff structure that has a good locking effect and can effectively prevent unlocking by improper means or articles other than the key.
2. Prior art
As shown in FIG. 1, the conventional handcuff structure has a chain D (or a steel cord or other similar connection member) that connects two handcuff main bodies C (it is also possible to connect a single handcuff main body C at a fixed position). Each handcuff body A is comprised of two fixed, arc-shaped hooks 1, 10 and a movable ring hook 20 that rotate relative to each other about a pivot 100. The two fixed ring hooks 1, 10 are engaged with each other at the other end. There is an accommodation chamber 11. A horizontal side hole 13 connected to the outside is provided on said accommodation chamber 11 at the end adjacent to fixed ring hooks 1, 10. A connected key recessed part 12 is provided at the other end of said accommodation chamber 11. Said key recessed part 12 can be connected to the outside via a key hole 121. A plurality of projecting teeth 21 are provided on the outer periphery at the other free end of said movable ring hook 20. One end of a locking member 3 is pivoted in accommodation chamber 11 on the side away from key recessed part 12. The other end of said locking member 3 has a side projecting part 31 that can stick into said key recessed part 12. A projecting part 32 that extends upwards is provided on the side of said side projecting part 31. A plurality of lock projecting teeth 33 are provided at the other (free) end of locking member 3 corresponding to the open side of accommodation chamber 11. A stop block 5 is provided on the top side in accommodation chamber 11. A side edge 51 extending toward key recessed part 12 is provided at its one end. An abutting part 52 extending downwards is provided on the side of said side edge 51. A plurality of alignment recessed parts 53 are provided on the side of said abutting part 52. A V-shaped elastic member 4 is provided between locking member 3 and stop block 5. One side of the elastic member is abutted against the top edge of said locking member 3, while the other side has at least one bent projecting part 41 to fit in the alignment recessed part 53 of stop block 5. Also, the elastic abutting of said elastic member 4 can make locking member 3 maintain the outward elasticity of its lock projecting teeth 33 from accommodation chamber 11. During use, when the free end of said movable ring hook 20 sticks into accommodation chamber 11, its projecting teeth 21 can be engaged with the lock projecting teeth 33 of locking member 3 to achieve locking. At that time, the arms and legs (usually, wrists) of a person can fit in the spaces defined between fixed ring hooks 1, 10 and movable ring hook 20 to restrain the person's movement. As shown in FIG. 2, if a thin push rod penetrates through side hole 13 from outside, it can push stop block 5 and make it slide. The abutting part 52 of stop block 5 can move to the right to the position where it abuts against the projecting part 32 of locking member 3 to achieve a reinforced locking state of the locking member 3 that is more difficult to unlock by illegal means. If it is necessary to unlock handcuff main body C under normal circumstances, a key can be inserted into key recessed part 12 from key hole 121. When the key is first turned counterclockwise, the projecting abutting part at the end of the key pushes stop block 5 to move in the opposite direction (to the left) to release the abutting state of its abutting part 52 against projecting part 32 on the top. Then, the projecting abutting part of the key is turned clockwise so that the projecting abutting part can push the side projecting part 31 of locking member 3 upwards. As a result, locking member 3 pivots and lock projecting teeth 33 are disengaged from the projecting teeth 21 of movable ring hook 20 (and pressing elastic member 4 at the same time) so that movable ring hook 20 can pivot in the opposite direction, and its free end is disengaged in accommodation chamber 11 to release the aforementioned locking state. However, since the aforementioned locking structure and theory are relatively simple and the shape of the key has no complicated variations, anybody can unlock the handcuffs with a thin wire having a hook instead of the key. Therefore, the locking effect is extremely poor in practical application, which always causes troubles to the user.
Therefore, the structure shown in FIG. 3 is disclosed. The handcuff main body B is based on the structure shown in FIG. 1. It has the same fixed ring hooks 1, 10, movable ring hook 20, and other basic structures. The only difference is that locking member 3, elastic element 4, and stop block 5 have locking member 30, elastic member 40, and stop block 50 having exactly the same structures provided on their side, respectively. Two groups of independent locking mechanisms are formed by said locking member 3, elastic element 4, and stop block 5 as well as locking member 30, elastic member 40, and stop block 50 to lock said movable hook ring 20. When a thin wire having a hook is inserted and turned, it can only unlock one group of the locking mechanism, that is, locking member 3, and stop block 5 (or locking member 30, and stop block 50), while the locking member 30, and stop block 50 (or locking member 3, and stop block 5) are still in the locking state. In this way, it is possible to effectively prevent the handcuffs from being unlocked by any non-key, hook-shaped article. However, relatively big spaces 14, 141 (as shown in FIG. 4) are usually left between said movable ring hook 20 and the front, rear sides of accommodation chamber 11 so that the projecting teeth 21 of movable ring hook 20 can easily penetrate into (or pass through) the open side of accommodation chamber 11 (to engage with the lock projecting teeth 33 of locking member 3). Therefore, with adequate force, anybody can stick a narrow body 7 into spaces 14, 141. As a result, said narrow body is inserted between the projecting teeth 21 of movable ring hook 20 and the lock projecting teeth 33 of locking member 3 and disengage them from each other to unlock the handcuffs. This is a serious problem in application.
In order to solve the aforementioned problems of the conventional handcuffs, the present designer has conducted extensive research. The present design was reached as a result of this research.